﻿using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Test
{
    class Program
    {
        static void Main(string[] args)
        {
            //常量及变量
            const double PI = 3.14;
            double r = 3;
            double per = 2 * PI * r;
            double area = PI * r * r;
            Console.WriteLine("圆的周长为：{0}，圆的面积为：{1}",per,area);

            //命名规则
            string userName = "黄炎榕";
            string UserName = "Hyr";
            Console.WriteLine("我的中文名叫{0}，我的英文名叫{1}",userName,UserName);

            //if...else
            double Score = 59.5;

            if (Score>=90)
            {
                Console.WriteLine("优秀");
            }
            else if (Score>=80)
            {
                Console.WriteLine("良好");
            }
            else if (Score>=60)
            {
                Console.WriteLine("及格");
            }
            else
            {
                Console.WriteLine("不及格");
            }

            //switch...case
            Console.WriteLine("请输入您的成绩：");
            int result = int.Parse(Console.ReadLine());

            switch (result/10)
            {
                case 10:
                    Console.WriteLine("满分");
                    break;
                case 9:
                case 8:
                    Console.WriteLine("厉害");
                    break;
                case 7:
                case 6:
                    Console.WriteLine("666");
                    break;
                default:
                    Console.WriteLine("牛批！完美避开所有正确答案！！！");
                    break;
            }
            Console.ReadLine();
        }
    }
}
